Multiple recorder



Oct. 31, 1950 LEEDY ETAL 2,528,279

MULTIPLE RECORDER Filed Oct. 19, 1945 2 Sheets-Sheet 1 123222.222 0P5 HH/dflfl F. Leedy Oct. 31, 1950 H. A. LEEDY ETAL 2,528,279

MULTIPLE RECORDER Filed Oct. 19, 1945 2 Sheets-Sheet 2 Patented Oct. 31, 1950 UNITED STATES PATENT OFFICE MULTIPLE RECORDER Haldon A. Leedy and Marvin- 'Canir'as', chicago. T1 Ill., assignors to Armour Research Foundation" of Illinois Institute;of-Technology.'Chic'agoJlL,

a corporation of Illinois Application October 19, 1945, Serial No. 623,254

2 Claims." (Cl. 179100;2)

This invention relates to a magnetic wirerecording system and is specifically directed to an inexpensive method of making low cost duplicate magnetic wire recordings from a master wire F. record, which .recording method involves a miniduplicate'wire records are'ready for reproduction;

vice a'microphone is connected to an electromagnethaving closely spaced confronting poles. Between these poles travels .a paramagnetic wire,

about that of human hair. Sound waves vibrate the microphone diaphragm causing. variations head. The wire passing between the poles is thus longitudinally magnetized in incremental portions in accordance with the strength of the varying current. The pattern of magnetism or the magnetic record laid on the wire is thepremicrophone.

between the poles of the electroma'gnet or remum amount of winding of the Wires before the such as of stainless steel, having a diameter in electric current in the electromagnet, generally referred to as the recording or reproducing cise counterpart of the sound that entered the.

When the wire, thus magnetized, is fed again;

cording-reproducing head, this time the electro-L i magnet being connected with a loudspeaker in- In a wire magnetic recording-reproducing destead of a' microphone, the variation of electri cal impulses recreates the sound faithfullyp During both the recording and reproducing provide a novel method of making many dupli-' cate wire records at one time involving running the master wire record at faster speed than the duplicate wire records so that for a particular recording a smaller length of wire is usedfor the duplicate wire records thereby making such records relatively inexpensive.

A further object of this invention isto provide a novel apparatus for making a large number of duplicate wire recordsfrom asingle master record' wherein the supply spools-for' the duplicate L wire records'are arranged in banks.

A stillfurther object of this invention is to provide a novel method of duplicating wire rec-' ordsso' as to involve a minimum handling of the wire by virtueof the fact that the recording is done-backwards as the wire is being drawn in order to save additional rewinding and winding Y operations.

A still fu'rther object of this'invention is to provide' multiple wire recording apparatus'involving a minimum time to effect change-over from one spool of wire to another.

.Other objects and advantages will become apparent from a study of the following specification taken With the accompanying drawings wherein:

Fig'. l is a diagrammatic showing of a vertical plan view of a wire record duplicating system involving the principles of this invention;

Fig. 2 is a-diagrammatic showing of a modified dorm of apparatus similar in some respects to that shown in Fig. 1;

Fig. 3 shows one form of multiple drive to effectdrive of the various spools by means of a drive roller.

Fig. 4 is a modification of the drive shownin Fig. 3 wherein a belt is used for individual spool drive, and

Fig. '5 is a further modification of the roller drive means including a quick change-over fea ture.

Referring more particularly to Fig. 1 numerals l to 12 inclusive denote a plurality of supply or storage spools for feeding a plurality of strands of paramagnetic wire onto a capstan 13. The

various strands of wire may make a single loop about the capstan or, if desired, may be wrappedtherearound only a fraction of a loop. The capstan is driven'by a suitable motor (notshown) so that the various strands of wire are moved longitudinally at a speed depe'ndingupon the speedi of rotation of the capstan. 'Spools I a to [2a in-,' elusive are take-up spools. While the spool banks are shown staggered for purposes of simplicity it will be apparent they may be located directly above each other so that the wire spacing on' the less than the spool spac-" capstan is considerably ing.

An outstandingfeature of this invention is that of providing a large diameter portion M on the I. capstan about which a master wire record I6 is entrained, fed from a supply spool I1 while pro,-

viding a small diameter portion I5 of the capstan about which the various wire records which arebeing duplicated in accordance with the pattern of the master'wire record are entrained. It will be seen, therefore, that for a given rotational speed of the capstan the master wire record will travel faster longitudinally than the various wire records being duplicated and the greater the ratio of portion M to portion [5 the faster will be the relative speed of the master wire record to that of the duplicate wire records.

Such difference in speed is desirable because for most faithful reproduction, the master wire record should be recorded at relatively high speed to obtain faithful reproduction of a fuller range of frequencies, particularly the higher frequencies. A desirable speed for recording, hence for reproducing the master wire record, is in the neighborhood of 5 ft. per second. However, for duplicating recordings for home use where cost is an important item the spools would be too bulky and the wire bearing the record would be too long if the duplicate wires were run at the same relatively high speed. For this reason it is desirable to run the duplicate wire records at a smaller speed, such as, for example, about 2 ft. per second so that smaller lengths of wire will be used for a particular recording appearing on the master wire record. Thus a great savings of wire is efiected so that the cost of the duplicate wire record is relatively low hence the user is enabled to enjoy a large number of different magnetic wire recordings of relatively small size and at relatively low cost as compared to the cost of the master wire record.

The master wire record longitudinally travels across closely confronting poles of an electromagnet or pick-up whereby magnetic variations caused by variations in the magnetic pattern of the master wire record in a longitudinal direction are converted to variation in current in the coil 2! of the electromagnet. Coil 2! is connected to the input of an amplifier 22, the output of which is connected to a plurality of electromagnetic recording heads 23, 24, etc. whereby duplicate records are made on the wires coming from the smaller diameter portion of the capstan head corresponding to the master wire record whereby a plurality of duplicate records ma be made at one time.

It will be observed that when wire records are duplicated in the normal way, that is, in exact accordance with the sequence of variations appearing on the master wire record it will be necessary to rewind such wires on a supply spool before the wire is ready for reproducing. Or if the recording operation were not done simultaneously with the drawing operation, as will be described hereinafter, only an additional winding operation of the wire would be required, namely that for recording.

A further important aspect of this invention, therefore, is to make duplicate wire recordings in such manner as to require a minimum number of winding or rewinding operations.

Figure 2 shows a modification of the invention wherein wire drawing apparatus of any well known type, illustrated schematically by the block diagram since the details of such apparatus form no partof this invention, will feed a plurality of strands of wire directly to the small diameter portion of the capstan and through the magnetic recording or duplicating apparatus. Only four instead of twelve wires are shown in the interest of simplicity.

In order to eliminate any further winding or rewinding operation of the wire the magnetic wire record is fed backwards onto the large diameter portion of the capstan hence th se- 'w recording hence will be relatively inexpensive;

4 quence of magnetic variations impressed on the plurality of wires will be the reverse of the sequence of magnetic variations originally impressed on the master magnetic wire record.

In other words the tail end of a musical composition or program will be represented b the wire portion closest to the drums of the spools while the beginning of the musical composition will be represented by the wire portions outermost from the spools. Therefore it will be read= ily seen that the spools are immediately ready for magnetic reproduction or playing in a magnetic reproducer Without the necessity of a further rewinding operation as would otherwise be necessary.

It will be apparent that the feature of longitudinally moving the plurality of wires at a slower rate than that of the magnetic wire record so as to conserve wire may be accomplished irrespective of whether the plurality of magnetic wire records have a longitudinal magnetic variation sequence which is the same or the reverse of the sequence appearing on the magnetic wire record, furthermore that the wire drawing process, if desired, need not necessarily be accomplished simultaneously with the reverse recording process described in. which event apparatus as shown in Fig. 1 may be used for the reverse recording process.

If desired two master records may be simultaneously driven on the capstan so that one is always being rewound while the other is being used for recording or duplication.

Fig. 3 shows one form of multiple drive for driving various spools simultaneously with constant speed take-up and with individual spool slippage. A long drive shaft 30 integral with the capstan frictionally drives a plurality of individual drive rolls, such as 3|, biased into frictional engagement with shaft 30 as well as the individual spools, such as 32, by means of a spring 33 which is normally under tension.

Fig. 4 shows a modified form of drive, namely a belt drive instead of a roller drive, wherein a belt 35 which is entrained about two drive rolls 36 and 31 is adapted to drive an individual spool such as 38. It will be noted that a plurality of belts, such as 35, each of which drives a separate spool are also entrained about drive rolls 36 and 31.

Fig. 5 shows a further modification which is similar in many respects to that shown in Fig. 3 that is, having a spring pressed idler roller 40 providing frictional drive between drive shaft 4| and the individual spool 42. Spool 42 and another spool 43 are pivotally mounted at the ends of a lever 44 which is pivoted at point 45. Spool 43 may be used for loading during the time that the wire on spool 42 is being used for recording purposes. As soon as the wires are completely unwound from spool 42 the loading spool 43 is swung into the position formerly occupied by spool 42 and the wire thereon is used for recording. At this time empt spool 42 becomes the loading spool. Thus, it will be seen that loading and unloading may occur while the machine is running, therefore, requiring a minimum changeover time.

It will be seen'therefore that we have provided a relatively simple method and apparatus for making duplicate magnetic wire recordings corresponding to that of a master wire recording, which duplicate recordings will involve a substantially shorter length of wire than the master further we have provided a method of impressing on a plurality of wires magnetic variations of inverse sequence of those appearing on a master wire record or other equivalent record (disk rec- 0rd etc.) which recording may be made simultaneously with the wire drawing process so that no further winding or rewinding of the wires is necessary.

While we have shown a particular embodiment of our invention, it will, of course, be understood that we do not wish to be limited thereto, since many modifications may be made, and we,

' therefore, contemplate by the appended claims to cover'all such modifications as fall within the true spirit and scope of our invention.

We claim as our invention:

1. In apparatus for duplicating, on a magnetizable elongated record member, a magnetic record corresponding .to that present on a master elongated record, including a rotatable capstan having a portion of relatively small diameter and a portion of relatively large diameter, said first mentioned magnetizable record being entrained about said small diameter portion and said master record being entrained about said large diameter portion during the recording process, a power driven take-up spool for taking said first record member from said small diameter pOrtiOn of said capstan and maintaining it taut therebetween, a second power driven take-up spool for taking said master record from said large diameter portion of said capstan and maintaining it taut therebetween, a magnetic pick-up head for said master record positioned between said capstan and said master take-up spool, and a magnetic recording head for said first record member posi tioned between said capstan and said first takeup spool, whereby said master record is driven longitudinally at a greater linear speed than the linear speed at which said first mentioned record is driven.

2. The combination comprising apparatus for drawing a magnetizable wire, a capstan upon which said wire is entrained immediately after it leaves said drawing apparatus, a power driven take-up spool for taking said wire from said capstan and maintaining said wire taut therebetween and a magnetic recorder positioned between said capstan and said take-up spool across which said wire travels to have a recording impressed thereon, said drawing apparatus and said recorder being operated simultaneously to impress a magnetic record on said magnetizable wire during the drawing process, which is backward from that of the original master record, thereby eliminating the necessity of further winding or rewinding of said wire before use in a magnetic reproducer.

HALDON A. LEEDY. MARVIN CAMRAS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

